I've been interested in that pattern for a while, since I've noticed it. What school do you go to? Has he published any of his stuff? I'm very interested.
As for this discussion...
There is no doubt temperament is a biological thing. While I'm sure extreme examples and people with illnesses can be exceptions, the evidence that personality generally stays the same in a person throughout their life is overwhelming. And more and more evidence links personality type with biochemistry.
But there's obviously a difference between biological factors and genetics in particular. Do I believe personality is, to some extent, genetic? Yes, I absolutely do. Do I think there's genes that literally code for, say, being an ENTP or an INFJ? No, of course not. Genetics itself is never that simple, and the biggest problem with that field has always been its reduction of phenotypes to single genes, when a systematic approach shows that can't be possible.
Such is the case with personality type. Your statement that a person is "born to be a certain type" intrigues me a lot; I think it's a fair proposition and explains what is likely the case. Though I am not at all open to the idea that you can mold a child in any way you want: temperament and type inherently destroy any attempt at a pygmalion project. If true personality, not outward appearance but true type, was so easily influenced by the environment, then there would hardly be any family conflicts to begin with.
I am certain that the foundation is set in each person at birth, but as you basically said, the intrastrengths of that person's type and how it is manifested outwardly will vary greatly on the environment. Obviously someone with a mental illnesses will see their brain chemistry falter, as will their type (e.g. someone who's bipolar or a schizophrenic). However, an NF raised in a family of Ss will vary greatly from an NF raised under N parents, but that doesn't mean the pattern of their brain chemistry won't be similar.
The brain is a self-organizing system with hundreds of millions of variables, different in everyone. It's also a two way street, and what happens in nurture will affect the nature (and vice versa). But on a conceptual scale, if we don't take personality types so concretely, they stay the same throughout life.
That said, the mere fact something like birth order is a recurring pattern with personality proves the biological issues are far more complex than mere genetics. But in the end, nurture is really just another section of nature.
Well, her name is Vicky Barton, but I'm honestly not sure if she has published anything on the topic; I wouldn't be surprised if she has though. But the school is on the Ball State University Campus.
Yes, I agree that nature is too elaborate and too complicated to make any definite conclusions without very extensive research of many different fields. That's one of the reasons why people are just "born" with their types; I don't see anything behind that. I know that genetics control the physical characteristics of people, even the chemicals in the brain, which would account for dynamics in temperament. I understand that would help influence some parts of type preferences to a degree; chemical activity could account for questions of who is more emotional, who is more prone to anger issues, who has trouble processing information, etc. There is definitely a chance that that might help to sway a persons preference one way or the other; I would like to see some statistics on whether certain preferences like T/F have certain chemical levels that help to determine that.
However, I still believe that, ultimately, environment influences preference enough that it is the "deciding factor", if you will. For instance; chemicals, as far as I know about their nature, would not do a whole lot in deciding whether a person is more prone to organization or more spontaneous, more J or more P. Certainly chemicals, in excess, may help that preference, but I think the way you're raised does more for that. The same with introversion/extroversion, N/S. That would explain better the occurance of a certain preference in a family of opposing preferences a bit better than genetics, as that wouldn't make sense unless it was some sort of genetic mutation or extremely recessive trait. But if it were recessive, then that would knock out the dominant trait because you must have both recessive traits present to show the tendency; if P tendencies were dominant and J tendencies were recessive, then two J parents could not give birth to a P.
Of course, that is in the consideration of it as a single gene, when it would probably be a group of genes, but generally it follows to a degree.
But, in an environmental dynamic, let's say that two people who were extremely disorganized, or extremely uncaring (for the sake of the arguement, we'll say they're unhealthy xxxPs), gave birth to two children, a couple years apart. If the children are left to their own devices and the parents don't pay much attention to them, then one of the children may actually need more organizing skills to help himself and his sibling get by, so they may be more J. Or let's say the parents are unhealthy Exxxs that let the children do their own thing; the kids might rely so much on each other and lack from others, especially if they lack parental affection, that they exhibit Ixxx characteristics instead. In fact, you could probably make changes to this scenario for each trait.
Now, that scenario showed how type might be brought out in extreme circumstances, but it is much easier to illustrate that way. In a "normal" situation, the influences would probably be much more subtle, much less easy to pin-point, and you'd also have to consider other factors; are the parents the ones doing most of the teaching? If they both work and some one babysits, then there might be a difference in what the child is learning. If they go to a daycare with other children, that might make a difference. If they watch more TV, that might make a difference. But no matter what, in the early years that child is learning what it means to be a person in a society, and they take cues from that society on how they should think and act.
I mean, genetics and being "born" with type is hard to imagine for me because humans are among the only animals that thing abstractly. If it were only genetics, then how could we think either emotionally or logically? How could we be intuitive or sensing? Nature, as we can see in other examples, does not account for that; it accounts most for instinct and biological build. But how we act as human beings is comprised in amazing degrees on our extraordinary ability to learn and to take from our environments.
And that's going to be a really long post, but that should kind of explain some of my reasoning on a more extensive level >.>